Amnesty International says Egypt's military failed to take necessary precautions to avoid civilian casualties during airstrikes last week against what Cairo said were militant targets in Libya.

Egypt launched the strikes following the beheadings of 21 Egyptian Coptic Christians in the Libyan city of Sirte by militants affiliated with the Islamic State group, which has captured parts of Iraq and Syria.

Egypt said the strikes were carefully planned.

Amnesty said Monday that its research into the Feb. 16 airstrikes in the eastern Libyan city of Darna found that at least two missiles struck a heavily populated residential area, killing a mother, her three children and three other civilians.

In a similar report last week, the New York-based Human Rights Watch said at least six civilians were killed in the airstrikes.